Rotor

ABSTRACT

A rotor includes: a rotor core having: a rotor shaft hole; and a plurality of magnet insertion holes; and a plurality of magnetic pole portions. The rotor core includes a plurality of refrigerant flow passage hole portions. A refrigerant flow passage hole portion includes: a first refrigerant flow passage hole located on a virtual line connecting a circumferential center of each magnetic pole portion and a center of the rotor core; and a pair of second refrigerant flow passage holes facing each other across the first refrigerant flow passage hole on both circumferential end portion sides of each magnetic pole portion. The first refrigerant flow passage hole and the pair of second refrigerant flow passage holes include inner radial side apex portions protruding radially inward. Outer peripheral walls of the pair of second refrigerant flow passage holes include outer radial side apex portions protruding radially outward.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of priority of JapanesePatent Application No. 2018-197884, filed on Oct. 19, 2018, the contentof which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a rotor of an electric rotary machine.

BACKGROUND ART

In JP-A-2010-081657, a rotor which includes a rotor shaft hole intowhich a rotor shaft is tightened, a refrigerant flow passage holeprovided radially outside the rotor shaft hole and having a plurality ofhole portions arranged in a circumferential direction, and anelectromagnetic portion provided radially outside the refrigerant flowpassage hole and having a plurality of magnet insertion holes into whichmagnets are respectively inserted has been disclosed.

JP-A-2010-081657 describes that a refrigerant flowing through therefrigerant flow passage hole provided in the rotor core is supplied toa coil end using a centrifugal force generated by rotation of the rotor.

With the upsizing of an electric rotary machine in recent years, thedecrease in performance of the electric rotary machine due to heatgeneration of the magnet cannot be ignored and a method for efficientlycooling the magnet is being sought. The rotor described inJP-A-2010-081657 cools coils of a stator and does not cool the magnetdisposed in the rotor. Therefore, the refrigerant flow passage holedescribed in JP-A-2010-081657 cannot be diverted as it is. In order tocool the magnet placed on the rotor, it is necessary to bring therefrigerant flow passage hole closer to the magnet. However, whenrefrigerant supply holes are arranged in a vicinity of the magnetic poleportion, there is a possibility that the refrigerant supply holes may bedeformed by a tightening load of the rotor shaft to the rotor shaft holeand an outer peripheral portion of the rotor core may be deformed.

SUMMARY

The invention provides a rotor having excellent cooling performancewhile suppressing deformation of an outer peripheral portion of a rotorcore due to a tightening load of a rotor shaft.

According to an aspect of the invention, there is provided a rotorincluding: a rotor core having: a rotor shaft hole to which a rotorshaft is tightened; and a plurality of magnet insertion holes providedalong a circumferential direction; and a plurality of magnetic poleportions constituted by magnets inserted into the magnet insertionholes, wherein: the rotor core includes a cooling portion having aplurality of refrigerant flow passage hole portions provided radiallyinward of the plurality of magnetic pole portions and arranged along thecircumferential direction; a refrigerant flow passage hole portion ofthe plurality of refrigerant flow passage hole portions includes: afirst refrigerant flow passage hole located on a virtual line connectinga circumferential center of each magnetic pole portion and a center ofthe rotor core; and a pair of second refrigerant flow passage holesfacing each other across the first refrigerant flow passage hole on bothcircumferential end portion sides of each magnetic pole portion; thefirst refrigerant flow passage hole and the pair of second refrigerantflow passage holes include inner radial side apex portions protrudingradially inward; and outer peripheral walls of the pair of secondrefrigerant flow passage holes include outer radial side apex portionsprotruding radially outward.

EFFECTS

According to the invention, since both the first refrigerant flowpassage hole and the second refrigerant flow passage hole include theinner radial side apex portions protruding radially inward, the innerradial side apex portion is deformed so as to be pushed radially outwardwith respect to the tightening load of the rotor shaft. As a result,since it is possible to absorb the tightening load of the rotor shaftand to suppress the deformation of the outer peripheral portion of therotor core, it becomes possible to arrange the refrigerant flow passagehole further on the outer peripheral side of the rotor core, and thusthe cooling performance of the rotor is improved. Also, since the outerperipheral wall of the second refrigerant flow passage hole includes theouter radial side apex portion protruding radially outward, therefrigerant flow path can be formed further on the outer peripheral sideof the rotor core, and thus the cooling performance of the rotor isimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a rotor core according to a first embodimentof the invention;

FIG. 2 is a partially enlarged view of FIG. 1;

FIG. 3A is an enlarged view of a hole portion of a first hole portiongroup;

FIG. 3B is a view illustrating a force acting when the outer radial sideapex portion of the first hole portion group is located inside anintersection point X;

FIG. 3C is a view illustrating a force acting when the outer radial sideapex portion of the first hole portion group is located at theintersection point X;

FIG. 3D is a view illustrating a force acting when the outer radial sideapex portion of the first hole portion group is located outside theintersection point X;

FIG. 4A is an enlarged view of a hole portion of a second hole portiongroup;

FIG. 4B is a view illustrating a force acting on the hole portion of thesecond hole portion group; and

FIG. 5 is an enlarged view of a hole portion of a third hole portiongroup.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the invention will be described based onthe attached drawings.

[Rotor Core]

A rotor core 1 is configured by laminating a plurality ofelectromagnetic steel plates in an axial direction of a rotor shaft 2and constitutes a rotor 100 of a motor together with the rotor shaft 2and a plurality of magnets 3 assembled to the rotor core 1.

As illustrated in FIG. 1, the rotor core 1 has an annular shape in whicha rotor shaft hole 4 into which the rotor shaft 2 is tightened bypress-fitting is provided at a center CL. The rotor core 1 includes afirst hole portion group 6 having a plurality of hole portions 5provided on the outer side of the rotor shaft hole 4 in a radialdirection and arranged in a circumferential direction and a shaftholding portion 7 provided between the rotor shaft hole 4 and the firsthole portion group 6 in the radial direction. Further, the rotor core 1includes a second hole potion group 9 having a plurality of holeportions 8 provided on the outer side of the first hole portion group 6in the radial direction and arranged in the circumferential directionand a first annular portion 10 provided between the first hole portiongroup 6 and the second hole portion group 9 in the radial direction.Further, the rotor core 1 includes a third hole potion group 12 having aplurality of hole portions 11 provided on the outer side of the secondhole portion group 9 in the radial direction and arranged in thecircumferential direction, a second annular portion 13 provided betweenthe second hole portion group 9 and the third hole portion group 12 inthe radial direction, a cooling portion 33 having a plurality ofrefrigerant flow passage hole portions 30 provided on the outer side ofthe third hole portion group 12 in the radial direction and arranged inthe circumferential direction, and an electromagnetic portion 15provided on the outer side of the refrigerant flow passage hole portion30 in the radial direction and having a plurality of magnet insertionholes 14 into which the magnets 3 are respectively inserted.

[Electromagnetic Portion]

The electromagnetic portion 15 is disposed on an outer peripheralportion of the rotor core 1 and faces a stator (not illustrated). In theelectromagnetic portion 15, a plurality of magnetic pole portions 20 areformed at regular intervals along the circumferential direction. Each ofthe magnetic pole portions 20 is constituted of three magnets 3 insertedinto three magnet insertion holes 14 arranged in a substantially arcshape which protrudes inward in the radial direction. The magnet 3 is,for example, a permanent magnet such as neodymium magnet. It ispreferable that the magnetic pole portion 20 be configured such that acircumferential center portion is located radially inward of the rotorcore 1 with respect to both circumferential end portions. For example,the magnetic pole portion 20 may be constituted of two magnets arrangedin two magnet insertion holes arranged in a substantially V-shapeopening radially outward or it may be constituted by one arc magnetarranged in one magnet insertion hole formed in an arc shape convexradially inward.

[Cooling Portion]

The cooling portion 33 is disposed radially inward of theelectromagnetic portion 15 and has a plurality of refrigerant flowpassage hole portions 30 disposed along the circumferential direction.The refrigerant flow passage hole portion 30 communicates with arefrigerant supply path (not illustrated) provided inside the rotorshaft 2. The refrigerant flows axially from one side of the refrigerantflow passage hole portion 30 to the other side, thereby cooling themagnet 3 arranged in each magnetic pole portion 20. The refrigerant mayflow from the center of the refrigerant flow passage hole portion 30 inthe axial direction to both sides to cool the magnet 3 disposed in eachmagnetic pole portion 20. The refrigerant which cooled the magnet 3disposed in each magnetic pole portion 20 may be discharged to theoutside from an end surface of the rotor core 1 or may return to therotor shaft 2.

[Arrangement of Refrigerant Flow Passage Holes]

The refrigerant flow passage hole portion 30 includes a firstrefrigerant flow passage hole 31 located on a virtual line L1 connectingthe center of each magnetic pole portion 20 and a center CL of the rotorcore 1 and a pair of second refrigerant flow passage holes 32 located onimaginary lines L2 passing through circumferential end portions of eachmagnetic pole portion 20 and the center CL of the rotor core 1 andfacing each other across the first refrigerant flow passage hole 31. Thevirtual line L1 coincides with a d-axis, which is the center axis of themagnetic pole portion 20, and the virtual line L2 coincides with aq-axis, which is 90 degrees apart from the d-axis by an electricalangle.

Among both circumferential end portions of the magnetic pole portion 20,the second refrigerant flow passage hole 32 located on a circumferentialfirst end portion side is in common with the second refrigerant flowpassage hole 32 located on a circumferential second end portion side ofthe magnetic pole portion 20 adjacent to the circumferential first endportion side. In addition, among both circumferential end portions ofthe magnetic pole portion 20, the second refrigerant flow passage hole32 located on the circumferential second end portion side is in commonwith the second refrigerant flow passage hole 32 located on thecircumferential first end portion side of the magnetic pole portion 20adjacent to the circumferential second end portion side. That is, thefirst refrigerator flow passage holes 31 and the second refrigeratorflow passage holes 32 are alternately arranged in the circumferentialdirection.

Therefore, the refrigerant flows to the second refrigerant flow passagehole 32, and thus the circumferential first end portion side of themagnetic pole portion 20 and the circumferential second end portion sideof the magnetic pole portion 20 adjacent to the circumferential firstend portion side are cooled by one refrigerant flow passage, andsimilarly, the circumferential second end portion side of the magneticpole portion 20 and the circumferential first end portion side of themagnetic pole portion 20 adjacent to the circumferential second endportion side are cooled by one refrigerant flow passage. As a result,the structure of rotor core 1 can be simplified.

[Shape of Refrigerant Flow Passage Hole]

As illustrated in FIG. 2, the first refrigerant flow passage hole 31 hasa substantially pentagonal shape having an apex portion protrudingradially inward. The first refrigerant flow passage hole 31 has an outerradial side first end portion 31 a and an outer radial side second endportion 31 b which form both circumferential end portions of the outerradial side, an inner radial side first end portion 31 c and an innerradial side second end portion 31 d which form both circumferential endportions of the inner radial side, and an inner radial side apex portion31 e which is disposed on the virtual line L1, has a shorter radialdistance from the center CL of the rotor core 1 than the inner radialside first end portion 31 c and the inner radial side second end portion31 d, and forms a radial inner side apes portion.

Further, the first refrigerant flow passage hole 31 has an outerperipheral wall 31 f extending substantially linearly from the outerradial side first end portion 31 a to the outer radial side second endportion 31 b, an inner peripheral wall 31 g having a first innerperipheral wall 31 h extending substantially linearly from the innerradial side first end portion 31 c to the inner radial side apex portion31 e and a second inner peripheral wall 31 i extending substantiallylinearly from the inner radial side second end portion 31 d to the innerradial side apex portion 31 e, a first side wall 31 j extendingsubstantially linearly from the outer radial side first end portion 31 ato the inner radial side first end portion 31 c, and a second side wall31 k extending substantially linearly from the outer radial side secondend portion 31 b to the inner radial side second end portion 31 d.

The outer peripheral wall 31 f of the first refrigerant flow passagehole 31 is substantially orthogonal to the virtual line L1. The innerperipheral wall 31 g of the first refrigerant flow passage hole 31 has aconvex shape protruding radially inward. Furthermore, the innerperipheral wall 31 g of the first refrigerant flow passage hole 31 issubstantially parallel to an outer peripheral wall 11 e of the holeportion 11 of the third hole portion group 12 adjacent to a rib 18described below. More specifically, the first inner peripheral wall 31 hof the first refrigerant flow passage hole 31 is substantially parallelto a second outer peripheral wall 11 g of the hole portion 11 of thethird hole portion group 12 adjacent to the circumferential first endportion side of the rib 18 described below and the second innerperipheral wall 31 of the first refrigerant flow passage hole 31 issubstantially parallel to a first outer peripheral wall 11 f of the holeportion 11 of the third hole portion group 12 adjacent to thecircumferential second end portion side of the rib 18 described below.

A width W31 f of the outer peripheral wall 31 f of the first refrigerantflow passage hole 31 is shorter than a width W31 g of the innerperipheral wall 31 g.

Since the inner radial side apex portion 31 e of the first refrigerantflow passage hole 31 is arranged on the virtual line L1, the firstrefrigerant flow passage hole 31 deforms such that the inner radial sideapex portion 31 e is pushed radially outward with respect to atightening load of the rotor shaft 2. Due to the deformation of thefirst refrigerant flow passage hole 31, the tightening load of the rotorshaft 2 is absorbed by the first refrigerant flow passage hole 31. Onthe other hand, the outer peripheral wall 31 f of the first refrigerantflow passage hole 31 has a linear shape orthogonal to the virtual lineL1, a force acting on the outer peripheral wall 31 f by the tighteningload of the rotor shaft 2 has substantially no radial component at thecircumferentially central portion of the outer peripheral wall 31 f.Thereby, it can suppress that the outer peripheral portion of the rotorcore 1 deforms radially outward by the tightening load of the rotorshaft 2. Therefore, it is possible to suppress deformation of the outerperipheral portion of the rotor core 1 by the tightening load of therotor shaft 2 while absorbing the tightening load of the rotor shaft 2,the first refrigeration flow passage hole 31 can be arranged further onthe outer peripheral side of the rotor core 1. As a result, it ispossible to improve the cooling performance of the rotor 100.

The second refrigerant flow passage hole 32 has a substantiallyrectangular shape convex on both sides in the circumferential directionand both sides in the radial direction. The second refrigerant flowpassage hole 32 has a first end portion 32 a and a second end portion 32b forming both circumferential end portions, an outer radial side apexportion 32 c which is disposed on the virtual line L2, has a longerradial distance from the center CL of the rotor core 1 than the firstend portion 32 a and the second end portion 32 b, and forms a radiallyouter apex portion, and an inner radial side apex portion 32 d which isdisposed on the virtual line L2, has a shorter radial distance from thecenter CL of the rotor core 1 than the first end portion 32 a and thesecond end portion 32 b, and forms a radially inner apex portion.

In addition, the second refrigerant flow passage hole 32 includes anouter peripheral wall 32 e which has a first outer peripheral wall 32 fextending substantially linearly from the first end portion 32 a to theouter radial side apex portion 32 c and a second outer peripheral wall32 g extending substantially linearly from the second end portion 32 bto the outer radial side apex portion 32 c. Also, the second refrigerantflow passage hole 32 includes an inner peripheral wall 32 h which has afirst inner peripheral wall 32 i extending substantially linearly fromthe first end portion 32 a to the inner radial side apex portion 32 dand a second inner peripheral wall 32 j extending substantially linearlyfrom the second end portion 32 b to the inner radial side apex portion32 d.

The outer radial side apex portion 32 c of the second refrigerant flowpassage hole 32 is located radially outward of the innermost radialportion of the magnetic pole portion 20. As a result, since therefrigerant flow passage can be formed in the vicinity of thecircumferential end portion of the magnetic pole portion 20, the coolingperformance of the rotor 100 is improved.

In the outer peripheral wall 32 e of the second refrigerant flow passagehole 32 located on the circumferential first end portion side of themagnetic pole portion 20, the second outer peripheral wall 32 g issubstantially parallel to a radially inner end surface 3 a of the magnet3 disposed on the circumferential first end portion side of the magneticpole portion 20 and the first outer peripheral wall 32 f issubstantially parallel to a radially inner end surface 3 a of the magnet3 disposed on the circumferential second end portion side of themagnetic pole portion 20 adjacent to the circumferential first endportion side. Similarly, in the outer peripheral wall 32 e of the secondrefrigerant flow passage hole 32 located on the circumferential secondend portion side of the magnetic pole portion 20, the first outerperipheral wall 32 f is substantially parallel to a radially inner endsurface 3 a of the magnet 3 disposed on the circumferential second endportion side of the magnetic pole portion 20 and the second outerperipheral wall 32 g is substantially parallel to a radially inner endsurface 3 a of the magnet 3 disposed on the circumferential first endportion side of the magnetic pole portion 20 adjacent to thecircumferential second end portion side.

Thus, the second refrigerant flow passage hole 32 can be formed in thevicinity of the circumferential end portion of the magnetic pole portion20 while securing the q-axis magnetic path, so that the coolingperformance of the rotor 100 is improved without the q-axis inductancedecreasing.

In the inner peripheral wall 32 h of the second refrigerant flow passagehole 32 located on the circumferential first end portion side of themagnetic pole portion 20, the second inner peripheral wall 32 j issubstantially parallel to the first side wall 31 j of the firstrefrigerant flow passage hole 31 and the first inner peripheral wall 32i is substantially parallel to the second side wall 31 k of the firstrefrigerant flow passage hole 31 of the magnetic pole portion 20adjacent to the circumferential first end portion side. In the innerperipheral wall 32 h of the second refrigerant flow passage hole 32located on the circumferential second end portion side of the magneticpole portion 20, the first inner peripheral wall 32 i is substantiallyparallel to the second side wall 31 k of the first refrigerant flowpassage hole 31 and the second inner peripheral wall 32 j issubstantially parallel to the first side wall 31 j of the firstrefrigerant flow passage hole 31 of the magnetic pole portion 20adjacent to the circumferential first end portion side.

The inner radial side apex portion 32 d of the second refrigerant flowpassage hole 32 is arranged on the virtual line L2, so the secondrefrigerant flow passage hole 32 deforms so that the inner radial sideapex portion 32 d is pushed radially outward with respect to thetightening load of the rotor shaft 2. By the deformation of the secondrefrigerant flow passage hole 32, the tightening load of the rotor shaft2 is absorbed by the second refrigerant flow passage hole 32. As aresult, it is possible to arrange the second refrigerant flow passagehole 32 further on the outer peripheral side of the rotor core 1 whilesuppressing the deformation of the outer peripheral portion of the rotorcore due to the tightening load of the rotor shaft 2, and thus thecooling performance of the rotor 100 is improved.

Next, the first hole portion group 6, the second hole portion group 9,and the third hole portion group 12, which are disposed radially inwardof the cooling portion 33, and the first annular portion 10 and thesecond annular portion 13, which are formed by those hole portion groups6, 9, and 12, will be described. The first hole portion group 6, thesecond hole portion group 9, and the third hole portion group 12 and thefirst annular portion 10 and the second annular portion 13, which areformed by those hole portion groups 6, 9, and 12, function as regionsfor absorbing the centrifugal force due to the rotation of the rotor andthe tightening load of the rotor shaft 2.

[Arrangement of Hole Portions]

A rib 16 is formed between adjacent hole portions 5 of the first holeportion group 6. The rib 16 is disposed so that the circumferentialcenter position is located on the virtual line L1. Each hole portion 8of the second hole portion group 9 is arranged to intersect with thevirtual line L1. That is, the hole portions 5 of the first hole portiongroup 6 and the hole portions 8 of the second hole portion group 9 arealternately arranged in the circumferential direction. Thereby, thecentrifugal force can be absorbed by the hole portion 8 of the secondhole portion group 9 and the transfer of the centrifugal force to therib 16 can be suppressed.

Each hole portion 8 of the second hole portion group 9 of the embodimentis arranged so that the circumferential center position is located onthe virtual line L1. Furthermore, each hole portion 8 of the second holeportion group 9 has a circumferential length longer than that of the rib16 and circumferentially overlaps both adjacent hole portions 5 with therib 16 interposed therebetween.

A rib 17 is formed between adjacent hole portions 8 of the second holeportion group 9. The rib 17 is disposed so that the circumferentialcenter position is located on the virtual line L2. Each hole portion 11of the third hole portion group 12 is arranged to intersect with thevirtual line L2. That is, the hole portions 8 of the second hole portiongroup 9 and the hole portions 11 of the third hole portion group 12 arealternately arranged in the circumferential direction. Thereby, thecentrifugal force can be absorbed by the hole portion 11 of the thirdhole portion group 12 and the transfer of the centrifugal force to therib 17 can be suppressed.

Each hole portion 11 of the third hole portion group 12 of theembodiment is arranged so that the circumferential center position islocated on the virtual line L2. Furthermore, each hole portion 11 of thethird hole portion group 12 has a circumferential length longer thanthat of the rib 17 and circumferentially overlaps both adjacent holeportions 8 with the rib 17 interposed therebetween.

A plurality of hole portions 5 of the first hole portion group 6, aplurality of hole portions 8 of the second hole portion group 9, and aplurality of hole portions 11 of the third hole portion group 12 arearranged at equal intervals in the circumferential direction. Thereby,each of the hole portion groups 6, 9, and 12 can receive the centrifugalforce uniformly over the whole circumferential direction.

[Shape of Hole Portion]

As illustrated in FIG. 3A, each hole portion 5 of the first hole portiongroup 6 has a substantially triangular shape convex outward in theradial direction. The hole portion 5 of the first hole portion group 6has a first end portion 5 a and a second end portion 5 b which form bothcircumferential end portions and an outer radial side apex portion 5 cwhich has a radial distance from the center CL of the rotor core 1 islonger than that of the first end portion 5 a and the second end portion5 b and forms an apex portion on the radial outer side. Furthermore, thehole portion 5 of the first hole portion group 6 includes an outerperipheral wall 5 e which has a first outer peripheral wall 5 fextending substantially linearly from the first end portion 5 a to theouter radial side apex portion 5 c and a second outer peripheral wall 5g extending substantially linearly from the second end portion 5 b tothe outer radial side apex portion 5 c. Further, the hole portion 5 ofthe first hole portion group 6 includes an inner peripheral wall 5 hwhich is substantially orthogonal to the virtual line L2 and extendssubstantially linearly from the first end portion 5 a to the second endportion 5 b.

Each hole portion 5 of the first hole portion group 6 is deformed sothat the outer radial side apex portion 5 c is pulled radially outwardwith respect to the centrifugal force. The centrifugal force is absorbedby the hole portion 5 due to the deformation of the hole portion 5.Therefore, since it is possible to suppress the centrifugal force frombeing transmitted to the radial inner side of the rotor core 1, it ispossible to suppress the widening of the rotor shaft hole 4 due to thecentrifugal force and the reduction of the interference due to this.

Furthermore, since, in the hole portion 5 of the first hole portiongroup 6, the inner peripheral wall 5 h has a substantially straight lineshape substantially orthogonal to the virtual line L2, a force acting onthe inner peripheral wall 5 h when the centrifugal force acts on theouter radial side apex portion 5 c of the hole portion 5 hassubstantially no radial component at the circumferentially centralportion of the inner peripheral wall 5 h. Therefore, since deformationof the shaft holding portion 7 can be reduced, it is possible tosuppress the widening of the rotor shaft hole 4 due to the centrifugalforce and the reduction of the interference due to this.

The hole portion 5 of the first hole portion group 6 has the outerradial side apex portion 5 c located on the virtual line L2 and has asymmetrical shape with respect to the virtual line L2.

The outer radial side apex portion 5 c of the hole portion 5 of thefirst hole portion group 6 is located at an intersection point X betweena virtual line L4 which is orthogonal to a virtual line L3 connectingthe center CL of the rotor core 1 and the first end portion 5 a andpasses through the first end portion 5 a and a virtual line L6 which isorthogonal to a virtual line L5 connecting the center CL of the rotorcore 1 and the second end portion 5 b and passes through the second endportion 5 b or is located radially outward of the intersection point X.In the embodiment, the outer radial side apex portion 5 c of the holeportion 5 of the first hole portion group 6 is located radially outwardof the intersection point X.

As illustrated in FIG. 3B, when the outer radial side apex portion 5 cis positioned radially inward of the intersection point X, and acentrifugal force F acts on the outer radial side apex portion 5 c, abending stress Se in the radially inward direction is generated in theouter peripheral wall 5 e in addition to a tension Te. Therefore, in aregion around the first end portion 5 a and the second end portion 5 bof the outer peripheral wall 5 e, the bending moment becomes large andthe bending stress is concentrated.

On the other hand, as illustrated in FIG. 3C, since, when the outerradial side apex portion 5 c is located at the intersection point X, thefirst outer peripheral wall 5 f is along the virtual line L4 and thesecond outer peripheral wall 5 g is along the virtual line L6, even whenthe centrifugal force F acts on the outer radial side apex portion 5 c,almost no bending stress occurs in the outer peripheral wall 5 e.Therefore, stress concentration in a region around the first end portion5 a and the second end portion 5 b of the outer peripheral wall 5 e canbe alleviated.

As illustrated in FIG. 3D, when the outer radial side apex portion 5 cis positioned radially outward of the intersection point X, gaps areformed in a portion between the outer peripheral wall 5 e and thevirtual line L4 from the first end portion 5 a to the intersection pointX and a portion between the outer peripheral wall 5 e and the virtualline L6 from the second end portion 5 b to the intersection point X.Therefore, when the centrifugal force F acts on the outer radial sideapex portion 5 c, in addition to the tension being generated in theouter peripheral wall 5 e, the tension Th is generated in the innerperipheral wall 5 h. Thus, the stress generated in the hole portion 5 bythe centrifugal force F acting on the outer radial side apex portion 5 cis dispersed to the outer peripheral wall 5 e and the inner peripheralwall 5 h. As a result, the bending stress generated in the outerperipheral wall 5 e can be reduced and the stress concentration in theregion around the first end portion 5 a and the second end portion 5 bof the outer peripheral wall 5 e can be alleviated.

As described above, the outer radial side apex portion 5 c of the holeportion 5 of the first hole portion group 6 is located at theintersection point X between the virtual line L4 and the virtual line L6or located radially outward of the intersection point X. Thus, since itis possible to reduce the bending stress generated in the first outerperipheral wall 5 f and the second outer peripheral wall 5 g when acentrifugal force is generated, stress concentration in the regionaround the first end portion 5 a and the second end portion 5 b of theouter peripheral wall 5 e by the centrifugal force can be alleviated.

Since, in the hole portion 5 of the first hole portion group 6, theinner peripheral wall 5 h has a substantially linear shape, a forceacting on the inner peripheral wall 5 h when the centrifugal force actson the outer radial side apex portion 5 c of the hole portion 5 hasalmost no radial component in the circumferential central portion of theinner peripheral wall 5 h. Therefore, it is possible to suppress thewidening of the rotor shaft hole 4 due to the centrifugal force and thereduction of the interference due to this.

As illustrated in FIG. 4A, each hole portion 8 of the second holeportion group 9 has a substantially rectangular shape convex on bothsides in the circumferential direction and both sides in the radialdirection. Each hole portion 8 of the second hole portion group 9 has afirst end portion 8 a and a second end portion 8 b forming bothcircumferential end portions, an outer radial side apex portion 8 cwhich has a radial distance from the center CL of the rotor core 1longer than that of the first end portion 8 a and the second end portion8 b and forms a radially outer apex portion, and an inner radial sideapex portion 8 d which has a radial distance from the center CL of therotor core 1 shorter than that of the first end portion 8 a and thesecond end portion 8 b and forms a radially inner apex portion.Therefore, the hole area of the hole portion 8 can be increased, andthus the weight reduction of the rotor core 1 can be achieved. Inaddition, stress concentration in the first end portion 8 a and thesecond end portion 8 b due to the centrifugal force and the tighteningload of the rotor shaft 2 can be alleviated.

Further, the hole portion 8 of the second hole portion group 9 includesan outer peripheral wall 8 e which has a first outer peripheral wall 8 fextending substantially linearly from the first end portion 8 a to theouter radial side apex portion 8 c and a second outer peripheral wall 8g extending substantially linearly from the second end portion 8 b tothe outer radial side apex portion 8 c. In addition, the hole portion 8of the second hole portion group 9 includes an inner peripheral wall 8 hwhich has a first inner peripheral wall 8 i extending substantiallylinearly from the first end portion 8 a to the inner radial side apexportion 8 d and a second inner peripheral wall 8 j extendingsubstantially linearly from the second end portion 8 b to the innerradial side apex portion 8 d.

Each hole portion 8 of the second hole portion group 9 is deformed sothat the outer radial side apex portion 8 c is pulled radially outwardwith respect to the centrifugal force. The centrifugal force is absorbedby the hole portion 8 due to the deformation of the hole portion 8.Therefore, since it is possible to suppress the centrifugal force frombeing transmitted to the radially inner side of the rotor core 1, it ispossible to suppress the widening of the rotor shaft hole 4 due to thecentrifugal force and the reduction of the interference due to this.

Furthermore, the hole portion 8 of the second hole portion group 9 isdeformed so that the inner radial side apex portion 8 d is pushedradially outward with respect to the tightening load of the rotor shaft2. The tightening load of the rotor shaft 2 is absorbed by the holeportion 8 due to the deformation of the hole portion 8. Therefore, sinceit is possible to suppress the tightening load of the rotor shaft 2 frombeing transmitted to the radial outer side of the rotor core 1, it ispossible to suppress the deformation of the outer peripheral part of therotor core 1 due to the tightening load of the rotor shaft 2.

In the hole portion 8 of the second hole portion group 9, the outerradial side apex portion 8 c and the inner radial side apex portion 8 dare located on the virtual line L1 and the hole portion 8 has asymmetrical shape with respect to the virtual line L1.

The outer radial side apex portion 8 c of the hole portion 8 of thesecond hole portion group 9 is located at an intersection point Ybetween a virtual line L8 which is orthogonal to a virtual line L7connecting the center CL of the rotor core 1 and the first end portion 8a and passes through the first end portion 8 a and a virtual line L10which is orthogonal to a virtual line L9 connecting the center CL of therotor core 1 and the second end portion 8 b and passes through thesecond end portion 8 b or is located radially outward of theintersection point Y. In the embodiment, the outer radial side apexportion 8 c of the hole portion 8 of the second hole portion group 9 islocated radially outward of the intersection point Y.

Therefore, since the hole portion 8 of the second hole portion group 9can reduce the bending stress generated in the first outer peripheralwall 8 f and the second outer peripheral wall 8 g when the centrifugalforce is generated, it is possible to alleviate the stress concentrationin a region around the first end portion 8 a and the second end portion8 b of the outer peripheral wall 8 e due to the centrifugal force.

Further, the inner peripheral wall 8 h of the hole portion 8 of thesecond hole portion group 9 is parallel to the outer peripheral wall 5 eof the opposing hole portion 5 across the first annular portion 10. Morespecifically, the first inner peripheral wall 8 i of the hole portion 8of the second hole portion group 9 is substantially parallel to thesecond outer peripheral wall 5 g of the opposing hole portion 5 acrossthe first annular portion 10. Similarly, the second inner peripheralwall 8 j of the hole portion 8 of the second hole portion group 9 issubstantially parallel to the first outer peripheral wall 5 f of theopposing hole portion 5 across the first annular portion 10. Inaddition, a distance between the inner peripheral wall 8 h of the holeportion 8 and the outer peripheral wall 5 e of the opposing hole portion5 across the first annular portion 10 is a width W10 of the firstannular portion 10 (see FIG. 2).

As illustrated in FIG. 5, the hole portion 11 of the third hole portiongroup 12 also has the same shape as that of the hole portion 8 of thesecond hole portion group 9.

Each hole portion 11 of the third hole portion group 12 has asubstantially rectangular shape which is convex on both sides in thecircumferential direction and on both sides in the radial direction.Each hole portion 11 of the third hole portion group 12 has a first endportion 11 a and a second end portion 11 b which form bothcircumferential end portions, an outer radial side apex portion 11 cwhich has a longer radial distance from the center CL of the rotor core1 than the first end portion 11 a and the second end portion 11 b andforms a radially outer apex portion, and an inner radial side apexportion 11 d which has a shorter radial distance from the center CL ofthe rotor core 1 than the first end 11 a and the second end 11 b andforms a radially inner apex portion. Therefore, the hole area of thehole portion 11 can be increased, and thus the weight reduction of therotor core 1 can be achieved. In addition, stress concentration in thefirst end portion 11 a and the second end portion 11 b due to thecentrifugal force and the tightening load of the rotor shaft 2 can bealleviated.

Furthermore, the hole portion 11 of the third hole portion group 12includes an outer peripheral wall 11 e which has a first outerperipheral wall 11 f extending substantially linearly from the first endportion 11 a to the outer radial side apex portion 11 c and a secondouter peripheral wall 11 g extending substantially linearly from thesecond end portion 11 b to the outer radial side apex portion 11 c. Inaddition, the hole portion 11 of the third hole portion group 12includes an inner peripheral wall 11 h which has a first innerperipheral wall 11 i extending substantially linearly from the first endportion 11 a to the inner radial side apex portion 11 d and a secondouter peripheral wall 11 j extending substantially linearly from thesecond end portion 11 b to the inner radial side apex portion 11 d.

Each hole portion 11 of the third hole portion group 12 is deformed sothat the outer radial side apex portion 11 c is pulled radially outwardwith respect to the centrifugal force. The centrifugal force is absorbedby the hole portion 11 due to the deformation of the hole portion 11.Therefore, since it is possible to suppress that the centrifugal forceis transmitted to the radial inner side of the rotor core 1, it ispossible to suppress the widening of the rotor shaft hole 4 due to thecentrifugal force and the reduction of the interference due to this.

Furthermore, the hole portion 11 of the third hole portion group 12 isdeformed so that the inner radial side apex portion 11 d is pushedradially outward with respect to the tightening load of the rotor shaft2. The tightening load of the rotor shaft 2 is absorbed by the holeportion 11 due to the deformation of the hole portion 11. Therefore,since it is possible to suppress that the tightening load of the rotorshaft 2 is transmitted to the radial outer side of the rotor core 1, itis possible to suppress that the outer peripheral part of the rotor core1 is deformed by the tightening load of the rotor shaft 2.

In the hole portion 11 of the third hole portion group 12, the outerradial side apex portion 11 c and the inner radial side apex portion 11d are located on the virtual line L2 and the hole portion 11 has asymmetrical shape with respect to the virtual line L2.

The outer radial side apex portion 11 c of the hole portion 11 of thethird hole portion group 12 is located at an intersection point Zbetween a virtual line L12 which is orthogonal to a virtual line L11connecting the center CL of the rotor core 1 and the first end portion11 a and passes through the first end portion 11 a and a virtual lineL14 which is orthogonal to a virtual line L13 connecting the center CLof the rotor core 1 and the second end portion 11 b and passes throughthe second end portion 11 b or is located radially outward of theintersection point Z. In the embodiment, the outer radial side apexportion 11 c of the hole portion 11 of the third hole portion group 12is located radially outward of the intersection point Z.

Therefore, since the hole portion 11 of the third hole portion group 12can reduce the bending stress generated in the first outer peripheralwall 11 f and the second outer peripheral wall 11 g when the centrifugalforce is generated, it is possible to reduce the stress concentration ina region around the first end portion 11 a and the second end portion 11b of the outer peripheral wall 11 e by the centrifugal force.

Further, the inner peripheral wall 11 h of the hole portion 11 of thethird hole portion group 12 is parallel to the outer peripheral wall 8 eof the opposing hole portion 8 across the second annular portion 13.More specifically, the first inner peripheral wall 11 i of the holeportion 11 of the third hole portion group 12 is substantially parallelto the second outer peripheral wall 8 g of the opposing hole portion 8across the second annular portion 13. Similarly, the second innerperipheral wall 11 j of the hole portion 11 of the third hole portiongroup 12 is substantially parallel to the first outer peripheral wall 8f of the opposing hole portion 8 across the second annular portion 13.In addition, a distance between the inner peripheral wall 11 h of thehole portion 11 and the outer peripheral wall 8 e of the opposing holeportion 8 across the second annular portion 13 is a width W13 of thesecond annular portion 13 (see FIG. 2).

Returning to FIG. 2, the width W13 of the second annular portion 13 islarger than the width W10 of the first annular portion 10. That is, thewidth of the annular portion located on the radially outer side of therotor core 1 is larger and the width of the annular portion located onthe radially inner side is smaller.

Therefore, since the width of the annular portion located on theradially outer side of the rotor core 1 is larger, the rotor core 1 hasa higher rigidity toward the radially outer side and is less likely tobe deformed. Therefore, it can suppress that the outer peripheralportion of the rotor core 1 is deformed by the centrifugal force. Inaddition, since the width of the annular portion located on the radiallyinner side is smaller, the rotor core 1 has a lower rigidity toward theradially inner side and is likely to be deformed. As a result, thetightening load of the rotor shaft 2 can be absorbed by deformation sothat the annular portion located radially inward is expanded, and thusdeformation of the outer peripheral portion of the rotor core 1 can besuppressed.

Furthermore, the distance between the first end portion 5 a of the holeportion 5 and the second end portion 5 b of the hole portion 5circumferentially adjacent to the first end portion 5 a is a width W16of the rib 16. Similarly, the distance between the first end portion 8 aof the hole portion 8 and the second end portion 8 b of the hole portion8 circumferentially adjacent to the first end portion 8 a is a width W17of the rib 17. In addition, the distance between the first end portion11 a of the hole portion 11 and the second end portion 11 b of the holeportion 11 circumferentially adjacent to the first end portion 11 a is awidth W18 of the rib 18 located between the adjacent hole portions 11 ofthe third hole portion group 12.

The width W18 of rib 18 is larger than the width W17 of rib 17 and thewidth W17 of rib 17 is larger than the width W16 of rib 16. That is, thewidth of the rib located radially outward of the rotor core 1 is larger.

Therefore, since the width of the rib located on the radially outer sideof the rotor core 1 is larger, the rotor core 1 has a higher rigiditytoward the radially outer side and is less likely to be deformed.Therefore, it can suppress that the outer peripheral portion of rotorcore 1 is deformed by the centrifugal force. In addition, since the riblocated on the radially outer side of the rotor core 1 has a largerwidth, stress concentration on the rib due to the centrifugal force canbe alleviated.

Returning to FIG. 4A, an angle θ1 formed by the first outer peripheralwall 8 f and the second outer peripheral wall 8 g of the hole portion 8of the second hole portion group 9 and an angle θ2 formed by the firstinner peripheral wall 8 i and the second inner peripheral wall 8 j ofthe hole portion 8 of the second hole portion group 9 satisfy thefollowing equation (1), taking an angle formed by the first end portion8 a and the second end portion 8 b at the center CL of the rotor core 1as ϕ. Each of θ1 and θ2 is an angle larger than 0° and smaller than180°. ϕ is an angle larger than 0° and smaller than 360°/(the number ofmagnet pole portions 20 of rotor core 1). In the embodiment, since thenumber of magnet pole portions 20 of the rotor core 1 is 12, ϕ is anangle larger than 0° and smaller than 30°.θ1+2ϕ≥θ2≥θ1  (1)

As illustrated in FIG. 4B, when a centrifugal force F1 acts on the outerradial side apex portion 8 c of the hole portion 8, a force Fa acting ina direction toward the intersection point Y along the virtual line L8 isgenerated in the first end portion 8 a and a force Fb acting in adirection toward the intersection point Y along the virtual line L10 isgenerated in the second end portion 8 b, and further, a force F2 actingradially inward along the virtual line L1 is generated in the innerradial side apex portion 8 d.

Since the hole portion 8 of the second hole portion group 9 has asymmetrical shape with respect to the virtual line L1, assuming that thetension generated in the first outer peripheral wall 8 f by thecentrifugal force F1 is f1, the following equation (2) is established.F1=2×f1·cos(θ1/2)  (2)

Similarly, assuming that the tension generated in the first innerperipheral wall 8 i by the force F2 is f2, the following equation (3) isestablished.F2=2*f2·cos(θ2/2)  (3)

Assuming that an angle formed by the first outer peripheral wall 8 f andthe virtual line L8 at the first end portion 8 a of the hole portion 8of the second hole portion group 9 is θ3 and an angle formed by thefirst inner peripheral wall 8 i and the virtual line L8 at the first endportion 8 a is θ4, the following equation (4) is established.Fa=f1·cos θ3+f1·cos θ4  (4)

Further, since the force Fa acting on the first end portion 8 a actsonly in a direction toward the intersection point Y along the virtualline L8, the components orthogonal to the virtual line L8 cancel eachother and the following equation (5) is established.f1·sin θ3=f2·sin θ4  (5)

Further, since the hole portion 8 of the second hole portion group 9 hasa symmetrical shape with respect to the virtual line L1, the followingequations (6) and (7) are established.θ3=90°−(θ1+ϕ)/2  (6)θ4=90°−(θ2−ϕ)/2  (7)

From the equations (2) to (7), the following equation (8) is derived byeliminating f1, f2, θ3, θ4, and Fa.

$\begin{matrix}{{F\; 2} = {F\;{1 \cdot \frac{\cos\frac{{\theta\; 1} + \phi}{2}}{\cos\frac{{\theta\; 2} - \phi}{2}} \cdot \frac{\cos\frac{\theta\; 2}{2}}{\cos\frac{\theta\; 1}{2}}}}} & (8)\end{matrix}$

Here, since θ1, θ2, and ϕ satisfy the equation (1), the followingequations (9) and (10) are established.θ1+ϕ≥θ2−ϕ  (9)θ2≥θ1  (10)

Therefore, the following equations (11) and (12) are established.

$\begin{matrix}{\frac{\cos\frac{{\theta\; 1} + \phi}{2}}{\cos\frac{{\theta\; 2} - \phi}{2}} \leqq 1} & (11) \\{\frac{\cos\frac{\theta\; 2}{2}}{\cos\frac{\theta\; 1}{2}} \leqq 1} & (12)\end{matrix}$

Therefore, from the equations (8), (11), and (12), the centrifugal forceF1 acting on the outer radial side apex portion 8 c of the hole portion8 and the force F2 acting on the inner radial side apex portion 8 d bythe centrifugal force F1 always satisfy F2≤F1.

That is, in the hole portion 8 of the second hole portion group 9, theforce F2 acting on the inner radial side apex portion 8 d by thecentrifugal force F1 is always smaller than the centrifugal force F1acting on the outer radial side apex portion 8 c. As a result, since thereaction force of the force F2 acting on the inner radial side apexportion 8 d is always smaller than the centrifugal force F1, it ispossible to suppress the widening of the rotor shaft hole 4 due to thecentrifugal force and the reduction of the interference due to this.

In the hole portion 8 of the second hole portion group 9, the outerradial side apex portion 8 c and the inner radial side apex portion 8 dare located on the virtual line L1 and the hole portion 8 has asymmetrical shape with respect to the virtual line L1. Therefore, thehole portion 8 can further suppress the widening of the rotor shaft 4due to the centrifugal force and the reduction of the interference dueto this, and it is possible to more effectively absorb the tighteningload of the rotor shaft 2.

As illustrated in FIG. 5, an angle θ5 formed by the first outerperipheral wall 11 f and the second outer peripheral wall 11 g of thehole portion 11 of the third hole portion group 12 and an angle θ6formed by the first inner peripheral wall 11 i and the second innerperipheral wall 11 j of the hole portion 11 of the third hole portiongroup 12 satisfy the following equation (13), taking an angle formed bythe first end portion 11 i and the second end portion 11 b at the centerCL of the rotor core 1 as σ. Each of θ5 and θ6 is an angle larger than0° and smaller than 180°. σ is an angle larger than 0° and smaller than360°/(the number of magnet pole portions 20 of rotor core 1). In theembodiment, since the number of magnet pole portions 20 of the rotorcore 1 is 12, σ is an angle larger than 0° and smaller than 30°.θ5+2σ≥θ6≥5  (13)

Therefore, in the hole portion 11 of the third hole portion group 12,the force acting on the inner radial side apex portion 11 d by thecentrifugal force is always smaller than the centrifugal force acting onthe outer radial side apex portion 11 c. As a result, it is possible tosuppress the widening of the rotor shaft hole 4 due to the centrifugalforce and the reduction of the interference due to this.

Further, in the hole portion 11 of the third hole portion group 12, theouter radial side apex portion 11 c and the inner radial side apexportion 11 d are located on the virtual line L2 and the hole portion 11has a symmetrical shape with respect to the virtual line L2. Therefore,the hole portion 11 can suppress the widening of the rotor shaft 4 dueto the centrifugal force and the reduction of the interference due tothis, so it is possible to more effectively absorb the tightening loadof the rotor shaft 2.

Also, the plurality of hole portions 5 of the first hole portion group 6are all the same shape, and the plurality of hole portions 8 of thesecond hole portion group 9 are all the same shape, and further theplurality of hole portions 11 of the third hole portion group 12 are allthe same shape. Furthermore, the outer radial side apex portions 5 c ofthe plurality of hole portions 5 of the first hole portion group 6 arearranged such that all radial distances from the center CL of the rotorcore 1 are equal. The outer radial side apex portions 8 c of theplurality of hole portions 8 of the second hole portion group 9 arearranged such that all radial distances from the center CL of the rotorcore 1 are equal and the inner radial side apex portions 8 d of theplurality of hole portions 8 of the second hole portion group 9 arearranged such that all radial distances from the center CL of the rotorcore 1 are equal. The outer radial side apex portions 11 c of theplurality of hole portions 11 of the third hole portion group 12 arearranged such that all radial distances from the center CL of the rotorcore 1 are equal and the inner radial side apex portions 11 d of theplurality of hole portions 11 of the third hole portion group 12 arearranged such that all radial distances from the center CL of the rotorcore 1 are equal.

In this way, the first hole portion group 6, the second hole portiongroup 9, and the third hole portion group 12 can receive the centrifugalforce in a well-balanced manner and it is possible to equalize thedeformation in the plurality of hole portions 5 of the first holeportion group 6, the deformation in the plurality of hole portions 8 ofthe second hole portion group 9, and the deformation in the plurality ofhole portions 11 of the third hole portion group 12.

The first end portions 8 a and 11 a, the second end portions 8 b and 11b, the outer radial side apex portions 8 c and 11 c, and the innerradial side apex portions 8 d and 11 d of the hole portions 8 and 11 ofthe embodiment all have rounded corners in which the corners arerounded. However, the shapes of first end portion 8 a and 11 a, thesecond end portion 8 b and 11 b, the outer radial side apex portions 8 cand 11 c, and the inner radial side apex portions 8 d and 11 d can bechanged as appropriate.

In the embodiment, the hole portion 5 of the first hole portion group 6has a substantially triangular shape convex radially outward and thehole portion 8 of the second hole portion group 9 and the hole portion11 of the third hole portion group 12 have a substantially rectangularshape convex on both sides in the circumferential direction and bothsides in the radial direction. However, the shapes of hole portions 5,8, and 11 can be changed appropriately.

In the embodiment described above, modifications, improvements, and thelike can be made as appropriate.

At least the following matters are described in the presentspecification. In addition, although the constituent componentscorresponding in the embodiment described above are described inparentheses, it is not limited to this.

(1) A rotor (rotor 100) which includes a rotor core (rotor core 1)having a rotor shaft hole (rotor shaft hole 4) into which a rotor shaft(rotor shaft 2) is tightened and a plurality of magnet insertion holes(magnet insertion holes 14) provided along a circumferential directionand a plurality of magnetic pole portions (magnetic pole portions 20)constituted by magnets (magnets 3) inserted into the magnet insertionholes, where

the rotor core includes,

a cooling portion (cooling portion 33) having a plurality of refrigerantflow passage hole portions (refrigerant flow passage hole portions 30)provided radially inward of the plurality of magnetic pole portions andarranged along the circumferential direction,

a refrigerant flow passage hole portion of the plurality of refrigerantflow passage hole portion includes,

a first refrigerant flow passage hole (first refrigerant flow passagehole 31) located on a virtual line (virtual line L1) connecting acircumferential center of each magnetic pole portion and a center(center CL) of the rotor core, and

a pair of second refrigerant flow passage holes (second refrigerant flowpassage holes 32) facing each other across the first refrigerant flowpassage hole on both circumferential end portion sides of each magneticpole portion,

the first refrigerant flow passage hole and the pair of secondrefrigerant flow passage holes include inner radial side apex portions(inner radial side apex portions 31 e, 32 d) protruding radially inward,and

outer peripheral walls (outer peripheral walls 32 e) of the pair ofsecond refrigerant flow passage holes include outer radial side apexportions (outer radial side apex portions 32 c) protruding radiallyoutward.

According to (1), since both the first refrigerant flow passage hole andthe second refrigerant flow passage hole include the inner radial sideapex portions protruding radially inward, the inner radial side apexportion is deformed so as to be pushed radially outward with respect tothe tightening load of the rotor shaft. As a result, since it ispossible to absorb the tightening load of the rotor shaft and tosuppress the deformation of the outer peripheral portion of the rotorcore, it becomes possible to arrange the refrigerant flow passage holefurther on the outer peripheral side of the rotor core, and thus thecooling performance of the rotor is improved. Also, since the outerperipheral wall of the second refrigerant flow passage hole includes theouter radial side apex portion protruding radially outward, therefrigerant flow path can be formed further on the outer peripheral sideof the rotor core, and thus the cooling performance of the rotor isimproved.

(2) The rotor according to (1), where

an outer peripheral wall (outer peripheral wall 31 f) of the firstrefrigerant flow passage hole is substantially orthogonal to the virtualline, and

at least parts of the outer peripheral walls of the pair of secondrefrigerant flow passage holes are parallel to radially inner endsurfaces (radially inner end surfaces 3 a) of the magnets.

According to (2), since the outer peripheral wall of the firstrefrigerant flow passage hole is approximately orthogonal to the virtualline connecting the circumferential center of the magnetic pole portionand the center of the rotor, it is possible to suppress the deformationof the outer peripheral portion of the rotor core by the tightening loadof the rotor shaft. Also, since at least parts of the outer peripheralwalls of the pair of second refrigerant flow passage holes are parallelto the radially inner end surfaces of the magnets, the secondrefrigerant flow passage hole can be formed in a vicinity of thecircumferential end portion of the magnetic pole portion while securingthe q-axis magnetic path. Thereby, the cooling performance of the rotorcan be improved without reducing the q-axis inductance.

(3) The rotor according to (1) or (2), where

the second refrigerant flow passage hole located on a circumferentialfirst end portion side of the magnetic pole portion is in common withthe second refrigerant flow passage hole located on a circumferentialsecond end portion side of a magnetic pole portion adjacent to thecircumferential first end portion side, and

the second refrigerant flow passage hole located on the circumferentialsecond end portion side of the magnetic pole portion is in common withthe second refrigerant flow passage hole located on the circumferentialfirst end portion side of a magnetic pole portion adjacent to thecircumferential second end portion side.

According to (3), one refrigerant flow path can cool the circumferentialfirst end portion side of the magnetic pole portion and thecircumferential second end portion side of the magnetic pole portionadjacent to the circumferential first end portion side, and similarly,one refrigerant flow path can cool the circumferential second endportion side of the magnetic pole portion and the circumferential firstend portion side of the magnetic pole portion adjacent to thecircumferential second end portion side. As a result, the structure ofrotor core can be simplified.

(4) The rotor according to any one of (1) to (3), where

the magnetic pole portion has a shape in which the circumferentialcenter is located further on a radially inner side of the rotor corethan both circumferential end portion sides, and

the outer radial side apex portion of the second refrigerant flowpassage hole is located further on a radially outer side than aninnermost diameter portion of the magnetic pole portion.

According to (4), the outer radial side apex portion of the secondrefrigerant flow passage hole is located further on the radially outerside than the innermost diameter portion of the magnetic pole portion.As a result, since the refrigerant flow path can be formed in thevicinity the circumferential end portion of the magnetic pole portion,the cooling performance of the rotor is improved.

The invention claimed is:
 1. A rotor comprising: a rotor core having: a rotor shaft hole to which a rotor shaft is tightened; and a plurality of magnet insertion holes provided along a circumferential direction; and a plurality of magnetic pole portions constituted by magnets inserted into the magnet insertion holes, wherein: the rotor core includes a cooling portion having a plurality of refrigerant flow passage hole portions provided radially inward of the plurality of magnetic pole portions and arranged along the circumferential direction; a refrigerant flow passage hole portion of the plurality of refrigerant flow passage hole portions includes: a first refrigerant flow passage hole located on a virtual line connecting a circumferential center of each magnetic pole portion and a center of the rotor core; and a pair of second refrigerant flow passage holes facing each other across the first refrigerant flow passage hole on both circumferential end portion sides of each magnetic pole portion; the first refrigerant flow passage hole and the second refrigerant flow passage holes are alternately arranged in the circumferential direction; the first refrigerant flow passage hole includes: an outer peripheral wall extending substantially linearly; and an inner peripheral wall including an inner radial side apex portion protruding radially inward, the first refrigerant flow passage hole having a pentagonal shape having an apex portion protruding radially inward; the outer peripheral wall of the first refrigerant flow passage hole is substantially orthogonal to the virtual line; a width of the outer peripheral wall of the first refrigerant flow passage hole is shorter than a width of the inner peripheral wall of the first refrigerant flow passage hole; inner peripheral walls of the pair of second refrigerant flow passage holes include inner radial side apex portions protruding radially inward; and outer peripheral walls of the pair of second refrigerant flow passage holes include outer radial side apex portions protruding radially outward.
 2. The rotor according to claim 1, wherein: at least parts of the outer peripheral walls of the pair of second refrigerant flow passage holes are parallel to radially inner end surfaces of the magnets.
 3. The rotor according to claim 1, wherein: the second refrigerant flow passage hole located on a circumferential first end portion side of the magnetic pole portion is in common with the second refrigerant flow passage hole located on a circumferential second end portion side of a magnetic pole portion adjacent to the circumferential first end portion side; and the second refrigerant flow passage hole located on the circumferential second end portion side of the magnetic pole portion is in common with the second refrigerant flow passage hole located on the circumferential first end portion side of a magnetic pole portion adjacent to the circumferential second end portion side.
 4. The rotor according to claim 1, wherein: the magnetic pole portion has a shape in which the circumferential center is located further on a radially inner side of the rotor core than both circumferential end portion sides; and the outer radial side apex portion of the second refrigerant flow passage hole is located further on a radially outer side than an innermost diameter portion of the magnetic pole portion. 